Field of the Invention
The present invention relates to a technique for determining an image to be subjected to a character recognition processing.
Description of the Related Art
Conventionally, text information included in an image is acquired and used by performing an optical character recognition (OCR) processing on an image of a paper document. Further, in recent years, mobile terminals having camera functions have become widespread. Conventionally, a user used a scanner or the like to electronically capture a paper document, but it became possible to easily capture the paper document electronically by using a camera of a mobile terminal. For this reason, it is becoming common to perform the OCR processing on the image of the paper document photographed with the camera of the mobile terminal.
In a case where text information recognized by the OCR processing is used, an OCR accuracy becomes important. However, compared with an OCR accuracy for an image such as a business card or a license card that can be taken close to a target object, an OCR accuracy for an image obtained by photographing a relatively large paper document such as A4 or A3 with a camera is lowered. This is because a resolution per a character of the text to be recognized decreases as the distance between the camera and the target object increases. Therefore, in the case of the paper document of relatively large size such as A4 or A3, the OCR accuracy can be improved by capturing an image obtained by taking a close-up photograph of the text area to be recognized. However, blurring of the photographed image is likely to occur by merely taking the close-up photograph, and it is difficult to photograph an image with little hand-trembling, which is suitable for the OCR.
Japanese Patent Laid-Open No. 2010-277442 discloses a technique for taking a photograph using a camera of a mobile terminal and determining whether or not the picture is acceptable. Japanese Patent Laid-Open No. 2010-277442 is a technique for determining that an image of which edge information or the like of image data obtained by using a camera of a mobile terminal matches a predetermined condition is passed.